I read the short report by Hall et al
(2004) with interest. The
authors reported a marked impairment in the ability of people with
schizophrenia to make social judgements from facial expressions. Their
findings complement and extend earlier studies by us and others
(Hellewell et al,
1994; Edelstyn et al,
1996,
2003) that have reported the
presence of impairments in facial recognition memory. However, these
abnormalities in facial and emotion recognition do not appear to lead to
obvious difficulties in day-to-day life; for example, individuals do not
appear to exhibit problems with the recognition of familiar people. This
apparent inconsistency between experimental findings and real-life situations
raises issues about the role played by these cognitive abnormalities in
schizophrenia. It is likely that these impairments are stable abnormalities
rather than being transient indicators of dysfunction. This would be
consistent with structural or functional abnormalities in schizophrenia, which
only become evident when the processing systems are placed under high levels
of stress, for example, during the prodromal or psychotic phases of a
functional illness. This line of reasoning is supported by Hall et
al’s finding that individuals with positive symptoms are unable to
identify even basic facial emotions. These inherent weaknesses within the
processing system may remain hidden during quiescent periods, but may be
artificially exposed in the laboratory by challenging the processing system
with particularly difficult tasks. Such deficits in visual processing, when
combined with other factors such as changes in mental state and impaired
cognitive reasoning, operate in a complex interaction to produce psychotic
episodes.

In an attempt to understand the basis of their findings, Hall et
al draw attention to the roles of the frontal and temporal cortices as
well as the amygdala. In addition to these, we believe that abnormalities in
the non-intentional, automatic acquisition of knowledge about the structural
relations between objects or events may contribute to impairments in social
cognition. Lewicki (1988) and
others have suggested that intuitive knowledge can influence how people form
impressions, draw inferences and react to situations and people.
Interestingly, a number of recent studies have reported the presence of
implicit learning abnormalities in people with schizophrenia (e.g. procedural
learning, word-stem completion, lexical and semantic priming)
(Schwartz et al,
2003). Future research might examine how those with schizophrenia
acquire implicit knowledge of regularities in social contexts and how this
knowledge relates to adaptive functioning in schizophrenia.

Author’s reply

Professor Oyebode draws attention to a number of interesting issues in
response to our study of social cognition and face processing in
schizophrenia. A key question raised by our study is why deficits in emotion
recognition were state-dependent, being limited to individuals experiencing
positive symptoms, while impairments in social cognition were stable. One
possibility, as discussed by Professor Oyebode, is that those who are free of
positive symptoms are able to use alternative cognitive strategies to identify
basic facial emotions. This view is supported by a functional magnetic
resonance imaging study in which individuals with schizophrenia, none of whom
was experiencing positive symptoms, were able to identify facial emotions
correctly but nevertheless showed deficits in amygdala activation when
processing facial affect (Gur et
al, 2002). These findings suggest that other brain regions
compensate for the normal functions of the amygdala in facial affect
processing when individuals with schizophrenia are free of positive symptoms.
More difficult tests, such as our social cognition task, may prevent such
compensation and thus reveal an underlying stable deficit.

Professor Oyebode also points out the apparent discrepancy between the
finding that people with schizophrenia have impairments in facial recognition
memory on formal testing, but are able to recognise familiar people in
day-to-day life. In our study we found no deficit in the ability of those with
schizophrenia to recognise the identity of novel faces presented concurrently,
suggesting that the deficits seen in previous studies resulted from the
mnemonic and attentional demands of the tasks used, which may be lower for
familiar people.